Bertje writes:

In a Dutch science quiz the following question is asked:

When will an astronaut in his spaceship outside the earth's atmosphere
begin to float?
A. When he's far enough away from earth's gravity
B. When his spaceship is hanging exactly between two gravity-fields
C. When he turns off the engine of his spaceship.

C. This is because he is in "free fall". This is, even though
earth's gravity is pulling on him, it's also pulling on his spaceship
causing the same (or very nearly so) acceleration.



I don't believe answer C is right. If he would shut of his engine he
would actually float, but once again different gravity-fields from
surrounding bodies would attract him

Doesn't matter. The different gravity fields attract the spacecraft
with the same acceleration. They accelerate in the same direction at
the same rate, so the astronaut appears to float in the frame of
reference of the spacecraft. In the frame of reference of the earth,
they are both "falling" around the earth in a path called an orbit.

Time to re-read Newton's laws of motion and how they relate to
orbits.

http://galileoandeinstein.physics.vi.../newtongl.html

Jeff
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